The present invention relates to a method for the production of a field-effect structure and to a field-effect structure as set forth herein.
German Published Patent Application No. 198 44 676 describes a field-effect structure in which appropriately doped drain and source regions are provided in a silicon substrate. A gate region, which is covered with a gate oxide, is arranged between the drain region and the source region. Above the gate region, a gate structure, which is designed as a movable bar, is arranged. A current flow between the source and the drain of the field-effect structure varies as a function of the position of the gate structure.
By contrast, the method for producing a field-effect structure and the field-effect structure, according to an example embodiment of the present invention, includes the advantage that the gate region may be produced in such a way that the field-effect structure""s long-term stability is improved. In particular, impurities in the gate region, which result in non-reproducible long-term changes in the field-effect structure""s electrical behavior, are avoided.
According to one example embodiment of the present invention, silicon and silicon oxide are suitable as the material for the substrate and for the gate oxide. The drain region and the source region may be created in a straightforward manner with a silicon substrate by implanting dopants. Etching of the germanium sacrificial layer may be accomplished via oxidizing agents in an aqueous solution and also by etching in the gas phase via a combination of oxidizing agents and halogens. To protect the gate oxide, a cover layer made of silicon may be provided so as to create hermetic packaging during the production process itself. This cover layer may then be closed off via a sealing layer.